1. Technical Field
The present invention relates to a semiconductor device, an electro-optic device, a power conversion device, and an electronic apparatus.
2. Related Art
Single-crystal silicon is large in size, high in quality, and low in price, and has been used as a base on which a single crystal of a variety of materials is grown.
Among these materials, cubic silicon carbide (3C-SiC), which is a wide-bandgap semiconductor material having a band gap as high as 2.2 eV (300 K), is promising as a low-loss semiconductor material for power device in the next generation, and is thought to be extremely useful also from a viewpoint in particular that it can be grown as a film or a single crystal (heteroepitaxy) on a low-price silicon substrate.
Incidentally, the lattice parameter of cubic silicon carbide is 0.436 nm, which is as smaller as roughly 20% than the lattice parameter (0.543 nm) of cubic silicon. Further, there is a difference of roughly 8% in thermal expansion coefficient between cubic silicon carbide and cubic silicon. Therefore, a lot of voids and misfit dislocations are apt to occur in the cubic silicon carbide grown as a single crystal, and it has been difficult to obtain a high-quality epitaxial film with little crystal defects.
The technology for solving such a problem has been studied, and in JP-A-11-181567, for example, a mask layer is formed on a surface of a substrate in which silicon carbide is grown, then an opening section is formed in the mask layer to thereby disclose the surface of the substrate on which epitaxial growth of single-crystal silicon carbide is performed, wherein the height of the opening section is set to be equal to or higher than 21/2 of the width of the opening section, and at the same time to a height exceeding the thickness of the single-crystal silicon carbide to be formed.
However, right above the mask layer there exist defects (coalesced defects) in an assembled portion formed of the single-crystal silicon carbide films assembled to each other. Therefore, when forming a semiconductor element on the surface of the single-crystal silicon carbide film, there is a case in which a depletion layer formed in the vicinity of the source region or the drain region of the semiconductor element traverses the coalesced defects. As a result, there is a problem that the leakage current increases to thereby degrade the device characteristics.